me and TeslaHV9 are working on a solar battery charger that can charge 3 AA (outputs 5 volts for 3.6 volt batterys) at once at .15 amps in direct sunlight. I was woundering if we would be using AA or like special battery packs.

I don't think we will be restricting our users to a certain battery pack, so you guys are just creating an option for them

So the idea is, you choose whichever you think is the best, but try to take into account these things -

Price - try to keep it low costAvailability - use things found easily all over the world, or give information about alternative components which are sold in other parts of the worldDanger - include warnings... if you are using Lithium batteries especially!Design - try to make your module noob-proof. Use connectors that can't be inserted the wrong way, or design them so that incorrect connection doesn't do any harm.Flexibility - Make your module flexible... Could they use a 6V battery? If not... do we need to design another module for this?

I'm not sure if it would be better, but it is made from 4 solar cells and I used the from those solar path lights. I was wondering if this setup would work with the batteries we are using for oscar.plus do I really NEED a diode?

or I could make a regular $50 board, hook up a transister to it, and then run the battry charging power through the transister, so the master could actually send a signal to "begin charging batteries". I think that would be pretty cool.

it would be alright but not entirely necessary...are we actually having a power module?i mean... wont the master have its power regulation ob its board?like the axon and $50 board do...what you can do to improve on this idea is have a circuit that senses the battery voltage and turns off when its full..there are many ic's out there that can do this for you..for the idea with the transistor:i think it would add too much complexity to the idea of a charger...because then you would have to have yet another chip on there to co-ordinate the I2C.just my thoughts...